The present invention relates generally to plating of finger connectors of printed circuit boards, and more particularly, is directed to a tool for aligning tape on a printed circuit board to facilitate such plating.
As is well known, printed circuit boards include a circuit wiring pattern printed thereon, with the circuit wiring pattern being electrically connected to circuit components mounted on the printed circuit boards. In addition, printed circuit boards have peripherally located finger connectors for inputting signals to, and for outputting signals from, the circuit wiring pattern.
Because the printed circuit board is attached to and removed from different connections, there is often repeated connection and disconnection of the finger connectors to external connections. Because of the need for better electrical connectability and the requirement for low contact resistance, the finger connectors are coated with a noble element, such as a gold alloy. An example of such a gold alloy that is used is a cobalt-gold alloy. Further, such gold alloy prevents corrosion of the finger connectors, and therefore, prevent oxidation of the finger connectors.
Therefore, when plating the finger connectors with the gold alloy, it is necessary to provide a mask for the printed circuit board so that the gold alloy is applied only to the finger connectors. In this regard, it is know to adhere tape over the peripheral portion of the printed circuit board, except over that area containing the finger connectors.
Although there presently exist taping machines, these machines cannot accurately align tape on printed circuit boards for several reasons. First, the tape has a tendency to stretch, so that misalignment easily occurs. Second, misalignment occurs if there is any telescoping of the tape. Accordingly, the tape adherence operation is performed manually.
However, for each set of finger connectors, three pieces of tape must be used, that is, one piece of tape below the set of finger connectors and one piece of tape on either side of the finger connectors, thereby leaving the set of finger connectors exposed. Because of this operation, alignment of the pieces of tape will vary with each set of finger connectors, and there will not always be correct alignment.
Further, this operation must be performed for both sides of each set of finger connectors of the printed circuit board. Generally, there are two sets of finger connectors on a printed circuit board. Thus, twelve pieces of tape must be used, which is wasteful and time consuming to apply.